The present invention relates to a digital camera, especially to a lens assembly of the digital camera, which has a non-step focusing function.
In the progress of semiconductor technology, many electronic devices of analogous circuit are replaced by the digital ones. Digital camera is one of the widely spread electronic devices. FIG. 1A and FIG. 1B illustrate the front view and back view of a conventional digital camera. As shown in FIG. 1A and FIG. 1B, conventional digital camera 100 includes a unique-focus lens assembly 102, a display monitor 110 on the back of the digital camera 100, and viewfinder 114 for selecting the object to be captured.
FIG. 2 shows a functional diagram of the conventional digital camera. As illustrated in FIG. 2, the digital camera 100 includes a unique-focus lens assembly 102, image capture apparatus (i.e. CCD, CMOS Sensor) 104, A/D converter 106, processing module 108, display monitor 110, and storage module 112. The unique-focus lens assembly 102 is utilized for allowing the reflected light of objects to pass through. The reflected light is then transformed into electric signals by the image capture apparatus 104. Thereafter, the electric signals are further transformed into digital signals by the A/D converter 106. The digital signals are then calculated and managed by the processing module 108. The display monitor 110 coupled with the processing module 108 is for displaying the image, which is taken by the image capture apparatus 104. The storage module 112 is applied for saving the digital signals from the processing module 108.
FIG. 3 portraits a unique-focus lens assembly of the conventional digital camera. As shown in FIG. 3, the unique-focus lens assembly 102 includes a lens 202, enclosure 204, aluminum plate 206, image capture apparatus (i.e. CCD, CMOS Sensor) 208, insulation plate 210, and focus adjustment means 212. The lens 202 allows the reflected light of any objects to pass through. The enclosure 204 has a first hole in its upper end and a second hole in its lower end. The first hole supports the lens 202, and the second hole is used for receiving the image capture apparatus 208. The focus adjustment means 212 is mounted near the side wall of enclosure 204. By revolving the focus adjustment means 212, the screw 212A would be driven upward or downward along the direction, which is perpendicular to the lens 202, thereby adjusting the focus of the lens 202. After the calibration of screw 212A achieved, the screw 212A is welded in the lens assembly 102, thereby fixing the focus of lens 202. The image capture apparatus 208 coupled with the second hole of enclosure 208 transforms the light reflected from the lens 202 into electric signals. Aluminum plate 206 is connected with the image capture apparatus 208 and enclosure 204. Insulation plate 210, which is coupled with the aluminum plate 206, is used for isolating the aluminum plate 206 from electrically connecting with the circuit of insulation plate 210.
The location of lens 202 is adjusted by rotating the screw 212A of the focus adjustment means 212. The lens 202 would be driven upward or downward along the perpendicular orientation to itself, so as to locate the focus of the lens 202. During the procedure of focus calibration, since there is a force perpendicular to the axial direction of screw 212A, it would probably horizontally offset the position of lens 202. Typically, for avoiding the offset, the lens assembly needs to be fixed rigidly. Furthermore, when the adjustment of the screw 212A finished, the screw 212A could be fixed by welding. Therefore, the lens assembly 102 of conventional digital camera could only have a unique-focus, and it would be unavailable to take the scenes out of the focus range or take them ambiguously.
Since that, how to improve the above problems of the conventional digital might be an important issue to the people skilled in the art.
An object of the invention is to provide a digital camera with a non-step focusing function so as to take scenes in different distances into pictures.
The present invention discloses a digital camera with a non-step focusing function, which comprises a non-step focusing lens assembly, image capture sensor (i.e. CCD, CMOS Sensor), A/D converter, processing module, display monitor, and storage module. The light reflected from any objects is passed through the non-step focusing lens, and transformed into electric signals by the image capture means. The electric signals are then transformed into digital signals. It is noticeable that the above functions, such as focusing and information transforming, are controlled and managed by the processing module.
The lens assembly comprises an enclosure, annular rotating means, gear assembly, spring, leaf spring, cap, and lens. The enclosure has a housing and haft. The housing has a lower hole for supporting the image capture apparatus, and an upper hole, which is consisted of three slope sets. Each slope set has a sub-slope and a main slope, the main slopes of the slope sets having a same gradient and being in a same height at highest points or lowest points of the main slopes. The annular rotating means having three extrusive portions is connected to the slope sets of enclosure. The gear assembly, which is supported by the haft of enclosure and connected with the annular rotating means, is applied for driving the annular rotating means. The spring is mounted on the first inner rim of the upper surface of the annular rotating means. The leaf spring is placed on the second inner rim of the upper surface of the annular rotating means. The cap having a hollow part is connected with the enclosure, and the lens connected with the cap allows the light to project on the image capture apparatus.
The annular rotating means could revolve on any slope sets to make sure that the lens assembly would move in the direction perpendicular to the slope sets, thereby adjusting the focus of lens assembly. As for the location of the focus, it is determined by the height of the main slopes.